The present invention relates to a posture control aid for the handicapped and, in particular, to a self-directed, manually operated assembly for stabilizing a user's legs relative to a position adjustable seating assembly and upright utility platform.
Wheelchair users and other individuals having limited lower trunk or leg control functions, overtime typically experience a progressive atrophying of the leg and calf muscles, due to the lack of use. Without the aid of an attendant, it is difficult for such individuals to achieve a measure of physical therapy to maintain the muscle tone of the legs. A supported transfer of body weight to the lower limbs is, however, particularly desirable in that such activity induces muscle activity with consequent blood flow to the exercised limbs.
Accordindly, a need exists for an assembly whereby a user may, without outside intervention, position himself/herself to obtain a manipulation of the lower trunk between fully seated and erect postures.
Although applicant is unfamiliar with any assembly providing for the combinational advantages of the present invention, applicant is aware of various powered lift assemblies which are disclosed in U.S. Pat. Nos. 4,569,094 and 4,725,056. Such assemblies either incorporate sling seats having no back support, as do a number of other commercial units of which Applicant is aware, or are of relatively complex constructions to rigidly brace the occupant fore and aft relative to the assembly.
Other powered wheelchairs of which Applicant is aware which include seat assemblies that provide for seated and upright postures are disclosed in U.S. Pat. Nos. 4,545,616; 4,456,086 and 4,054,319. The lift mechanisms for such assemblies are believed distinguishable in that they are either coupled to the seat back to raise the back and thereby induce a desired folding of a multi-hinged chair or include a motorized jacking screw coupled to a front edge of the seat platform to raise the edge and induce a desired folding action.
Applicant is also aware of wheelchairs including seat mounted, hydraulic assist cylinders, which facilitate a standing motion for users who have partial use of their lower limbs and which are disclosed in U.S. Pat. Nos. 4,632,455 and 4,569,556. U.S. Pat. No. 3,023,048 discloses another seat assisted device, but wherein the backrest does not simultaneously fold with the seat assembly.
Otherwise, none of the assemblies of which Applicant is aware provide for an assembly including a hand operated hydraulically actuated lifting mechanism or one including an integral upright utility platform from which knee/calf and mid-section supports extend to brace the user therebetween. Moreover none of such devices provide for a lift framework which includes a single follower arm for inducing a simultaneous folding of the backrest.